More than a dozen Texas state parks, including some of the most visited sites in the 95-unit system, are closed to the public as a result of damage caused by a month of heavy rains capped by torrential downpours over the Memorial Day weekend.

Portions of a dozen or so other state parks are closed to visitors, with most of the closures tied to flooding from rivers and reservoirs swelled with runoff from rains that have soaked much of the state over the past weeks.

More than half of Texas' state parks have suffered weather-related damage during the past month or so. A handful of those parks, including Blanco State Park, which was devastated by a record-setting surge of the Blanco River, could be wholly or partially closed for weeks as damage is repaired or, in the case of several parks on the shores of swollen reservoirs, flood water continues covering campgrounds and other facilities.

Many of the closures will be temporary, with parks reopening when floods recede, damage is addressed and park visitors' safety can be assured, said Steve Lightfoot, Texas Parks and Wildlife Department spokesman. But other closures could be imposed if additional rains cause more flooding.

"It's a constantly changing situation right now," Lightfoot said Wednesday. "A lot depends on what the weather does."

Threat of flooding along the lower Brazos River triggered park officials on Wednesday to add Brazos Bend State Park in Fort Bend County and Stephen F. Austin State Park in Austin County to the list of parks temporarily closed to visitors. Brazos Bend is one of the most popular parks in a state park system that annually attracts more than 8 million visitors, generates more than $744 million in economic activity, and pumps more than $202 million into household incomes of Texans.

Most of the closed or partially closed parks are in north-central and central Texas, the regions hardest hit by recent rains.

At Blanco State Park, action by park staff during unprecedented flooding this past Saturday night averted what could have been tragedy. Park staff, concerned about the potential for flooding, moved to get campers out of harm's way. By the time campers began evacuation of the campground, the rising river had cut off exit routes. Park staff moved the 70 or so campers to the park superintendent's home, which sat on high ground out of the reach of the wall of water that plunged down the Blanco River, sweeping away everything in its path.

"The park's staff did a tremendous job," Lightfoot said. None of the people in the park were injured. The park did, however, see significant damage to areas near the river and will remain closed for an undetermined period, Lightfoot said.

Bastrop State Park also remains closed after heavy rains caused the earthen dam creating a seven-acre lake in the park to fail, sending a wall of water through the park. Bastrop State Park, slowly recovering from a massive wildfire that incinerated much of the park in 2011, will remain closed until damage is assessed and clean-up accomplished.

Flooding on the Guadalupe River has closed two parks: Guadalupe River State Park, upstream from Canyon Lake (which is more than 15 feet above it's full mark) and Palmetto State Park near Gonzales.

In East Texas, flooding along Village Creek has Village Creek State Park closed until further notice.

Flooded roads or damage to roads leading to Enchanted Rock State Natural Area and Colorado Bend State Park have those sites closed, although they could reopen by the weekend.

All or part of several state parks adjacent to reservoirs are closed. At Lake Somerville State Park, where the reservoir is more than 17 feet above its full level, the Nail's Creek and Birch Creek units of the park are closed.

On Lake Ray Roberts, which is almost 11 feet above full, all units of the Ray Roberts Lake State Park are closed.

Most of Eisenhower State Park , adjacent to Lake Texoma, is closed. Texoma, on the flooding Red River, is more than 26 feet above its normal level.

The same situation - partial closure - applies at Cedar Hill State Park. Cedar Hill, near Dallas and one of the most visited parks in the state system, sits on the shore of Joe Pool Reservoir, which is almost 13 feet higher than normal.

High cost

TPWD officials said the agency doesn't have an estimate of how much it will cost to address damage caused by the recent storms and associated runoff and flooding. The agency is fielding an assessment team for that purpose, Lightfoot said. But repair costs are certain to run into the millions, he said. That cost will be compounded by the loss of revenue generated through park entrance and use fees - revenue used to fund park operations.

Texas state parks see their highest visitation - as much as 80 percent of annual visitation - between Memorial Day and Labor Day.